1. Field of the Invention
The present invention is a novel urethral plug which can be used as a medicine delivery system by patients suffering from lower urinary tract infections or other urine disorders and disorders of the urethra and bladder.
The lower urinary tract is subject to a variety of bacterial illnesses and other disorders, which can be further characterized as renal, urethral, bladder, urethral and urinary. For example, bacteria infections of the lower urinary tract are very common, and after infancy occur about ten times more often in women than in men. The main route of infections in women ascends from the vagina through the urethra to the bladder. The majority of urinary tract infections (UTIs) are caused by gram negative bacteria such as Escherichia coli (up to 85% of UTIs), Klebsiella sp., Proteus sp., Enterobacter (Aerobacter) aerogenes, and Pseudomonas aeruginosa. Occasionally gram positive pathogens may be involved, including Staphylococcus epidermis (albus), and Staphylococcus aureus. The most common UTI is bacteriuria, or the proliferation of bacteria within the urine; as many as 10% of adolescent girls have this condition, often in asymptomatic form. The condition is considered deserving of treatment at bacterial counts above 100,000 per ml, and acute at counts above 500,000 per ml or more. Bacteriuria may lead to, or stem from, infections of the urethra and/or bladder. Most such conditions involve urea-splitting bacteria which render the urine alkaline and favor the formation of calcified deposits and urinary stones, which in turn harbor and protect the proliferating bacteria.
Infections involving bacteria in the urine and/or in the superficial regions of the urethral and bladder tissues should be highly amenable to treatment by the release of antibiotics into the urine in the bladder, or onto the walls of the urethra. The present invention comprises the delivery of antibiotics to the infected areas utilizing modified urethral plugs.
This invention is equally applicable to and intended for use in, other urine disorders and disorders of the bladder or urethra such as (e.g.) interstitial cystitis which can be treated chemically, by the action of a drug.
2. Prior Art
The principal therapy for UTIs involves antibiotics such as sulfonamides, tetracycline, ampicillin or amoxicillin, trimethoprim, trimethoprim/sulfamethoxazole, or ciprofloxacin hydrochloride. Oral doses typically on the order of a gram per day are usually maintained for 7-10 days, although 1-3 days is often effective. Recurrent infections are common and may be treated with additional medicines such as cephalosporins, nalidixic or oxolinic acid, or nitrofurantoin. Although this antibacterial therapy has markedly improved the prognosis for most UTIs, current methods of administering antibiotics have certain disadvantages which can be overcome by the present invention. Using oral means to deliver medicines for other disorders of course suffer from the same disadvantages.
Oral administration of antibiotics for the treatment of lower UTIs involves high doses, because the medicine must pass through the stomach, be absorbed by the intestines, survive first pass metabolism in the liver, accumulate in the blood, and finally accumulate in the urine and urinary tract in sufficiently high concentration to kill pathogenic organisms. This method is a very indirect means of administration, and leads to prolonged high systemic concentration of antibiotics. Under such conditions, many antibiotics have harmful side-effects such as ototoxicity and nephrotoxicity. The side effects limit the selection of antibiotics, and under the best of circumstances still expose the patient to small but undesirable risks.
Urinary medicines can also be administered by means of inserting conventional Foley catheters up the urethra to the bladder and instilling solutions via the Foley urine tube. Although this method delivers medication to where it is most needed, it is rarely used, and is almost never used unless the infection occurs in an already catheterized patient. Indwelling catheters tend to hinder free movement by the patient, and they preserve stagnant urethral conditions favorable to bacterial growth. Efforts to address the problems of indwelling catheters by repeated insertion and removal, introduces more bacteria into the infected urinary tract and may actually aggravates the infection. Moreover, existing catheters are expensive and not designed for easy self-administration. In addition, existing catheters have an open lumen for draining urine which also would drain out any antibiotic, limiting the effectiveness of any instillation.